I 


V 


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A STUDY  OF  THE  RECOVERY  OF 
ALUMINA  FROM  A CLAY 


BY 


GEORGE  FERRIS  WATSON 


THESIS 

FOR  THE 

DEGREE  OF  BAGHELOROF  SCIENCE 


IN 

CHEMISTRY 

COLLEGE  OF  LIBERAL  ARTS  AND  SCIENCES 


UNIVERSITY  OF'  ILLINOIS 


1922 


5 


UNIVERSITY  OF  ILLINOIS 


__Augus_t__4___  _I92_3._ 


THIS  IS  TO  CERTIFY  THAT  THE  THESIS  PREPARED  UNDER  MY  SUPERVISION  BY 

G eo rge_  F 1 er ris  _ Wats on 

ENTITLED A__Stjudy_  _o  f_ _t  h_e_  Re  cj?  verv_ _of_ .Alumina.  Fr om_ _Q1  ay 


IS  APPROVED  BY  ME  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR  THE 
degree  of  _ _ B a c_h elo r _ of _ _S  c i_3 no e_ _i  n _ C_h  e m is t ry 


X 

7 


* rt  : > 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/studyofrecoveryoOOwats 


I wish  to  sincerely  thank  Prof.  S.  W.  Parr  and  Dr.  W.  S 
Putman  for  the  help  they  have  given  me  on  this  problem  and 
in  preparing  this  thesis. 


. 


. 


TABLE  OF  CONTENTS 


page 

1.  INTRODUCTION  I 

2.  HISTORICAL 4 

3.  THEORETICAL  8 

4.  EXPERIMENTAL  II 

(a)  The  Sample 

(b)  The  Analysis 

(c)  Decomposition  by  acids  and  alkali 

5.  DISCUSSION  OF  RESULTS  14 

6.  SUMMARY  16 

7.  BIBLIOGRAPHY  17 


1. 

A STUDY  OF  THE  RECOVERY  OF  ALUMINA  FROM  A CLAY. 

I.  INTRODUCTION 

The  use  of  metals  in  modern  times  has  reached  unprecedented 
heights.  Our  transportation,  buildings,  life,  prosperity,  and 
civilization  directly  depend  upon  its  production.  The  metallurgy 
of  iron  has  been  known  and  made  use  of  for  ages.  The  ancients 
were  familiar  with  the  uses  of  brasse  and  bronzes.  But  the  main 
demand  has  fallen  upon  iron  on  account  of  its  occurence,  known 
metallurgy,  desirable  qualities,  and  many  alloys.  The  oxides  of 
iron  compose  approximatly  five  per  cent  of  the  earths  crust. 
Thousands  of  chemists  and  Technical  men  have  devoted  their  time 
to  the  determination  of  the  properties,  metallurgy,  alloys  and 
possibilities  of  the  metal.  And  the  problems  are  ever  more  com- 
plex and  daily  more  is  discovered  as  to  the  characters  of  the 
metal  and  its  alloys. 

It  was  not  until  comparatively  recent  times  that  the  world 
has  been  concerned  with  the  rise  in  importance  of  a new  metal 
which  we  know  as  aluminum.  Aluminum  occurrs  in  the  ground  as  a 
clay  or  a bauxite  in  which  it  is  associated  with  the  elements 
silicon,  oxygen,  alkali  earths,  iron,  sodium  and  a few  of  the 
common  metals.  The  compounds  of  aluminum  are  very  important 
when  we  realize  that  they  make  up  eight  per  cent  of  the  earths 
crust.  Bo  that  it  is  very  evident  that  aluminum  is  every  bit  as 
important  as  iron. 

At  the  present  time  the  manufacture  of  aluminum  is  dependent 
upon  the  supply  of  the  mineral  bauxite.  This  mineral  is  a com- 
bination of  deaspore  (Al.9O3.3H2  ) and  brown  hematite  ( FE203. 


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3H..0.)  In  the  United  States  bauxitehas  been  mined  since  about 
1335,  and  this  supply  has  been  taken  from  four  states,  Alabama, 
Georgia,  Tennessee,  and  Arkansas.  'The  following  table  shows 
the  production  of  Bauxite  by  states  in  the  United  States 
Table  --I.  * 

Production  of  bauxite  in  the  United  States 

Alabama)-  27,409  -25,  003  -62,  164  -43,  076  -40,029 

Georgia) 

Tenn.  ) -132, 332  -272,  022  -506,  556  -333,490  -431,279. 

Arkansas  ) 

There  were  no  figures  available  on  the  estimated  reserves  of  the 
supply,  but  it  is  safe  to  conclude  that  these  deposits  are  cer- 
tainly only  a very  small  percentage  of  the  total  U.  S.  supply. 

It  is  regrettable  that  a metal  of  such  wide  occurence  and  such 
valuable  properties  is  obliged  to  owe  its  existence  to  a mineral 
of  such  comparatively  narrow  resources.  Also  in  order  for  a 
bauxitic  mineral  to  be  of  use  commercially  it  must  have  at  least 
fifty  percent  of  alumina  and  a low  percentage  of  silica  and  other 
impurities.  These  narrow  specifications  upon  the  production  of 
aluminum  will  in  years  to  come  hinder  the  use  of  the  metal  con- 
si  derably . 

The  production  of  aluminum  in  commercial  quantities  given 
rise  to  a thousand  and  one  uses.  On  account  of  its  extreme 
lightness  it  has  found  a ready  use  in  many  fields,  especially 
small  articles  as  keyes,  vi sting  cards,  thimbles,  cigarette  cases, 
etc.  Its  use  in  cooking  utensils  is  known  every  where  on  ac- 
count of  its  conductivity  and  resistance  to  acids.  It  has  been 
especially  valuable  in  military  equipment  for  its  lightness, 
resistance  to  oxidation,  and  strength.  Its  lightness  was  also 


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appreciated  in  the  automobile  andaeroplane,  and  a great  field 
was  opened  up  there.  And  it  is  now  a fact  that  aluminum  more 
than  holds  its  own  with  nickle,  copper,  brass,  and  even  iron. 
And  even  with  its  many  uses  very  little  is  known  concerning 
its  alloying  and  most  economic  metallurgy. 


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4. 

1 1. HI  STORY 

Aluminum  is  essentially  a modern  metal.  The  first  reference  to 
such  a metal  was  not  until  1760  when  Morveau,  in  Prance,  calcined 
an  alum  and  called  the  resulting  product  alumina.  Lavoisier  first 
suspected  the  existence  of  a metallic  base  of  earths,  and  he  sus- 
pected alumina  of  being  an  oxide  of  a metal  which  was  called 
aluminum. 

The  first  attempts  at  the  production  of  pure  aluminum  was 
started  in  1007,  and  the  general  process  was  the  reduction  by 
an  alkali  metal.  Due  to  the  meagre  knowledge  of  electricity  and 
electrical  apparatus  the  decomposition  by  this  method  was  never 
studied  closely,  although  Davy  did  try  this  method.  Wohler  was 
the  first  to  isolate  aluminum  and  he  accomplished  this  by  decom- 
position of  aluminum  cloride  with  potassium.  But  he  got  a fine 
gray  powder  which  could  not  be  used  for  the  determination  of  the 
properties  of  the  metal.  Later  in  1845,  Wholer  got  the  metalic 
form  by  passing  potassium  va  ors  over  aluminum  cloride  in  boats, 
^rom  globules  obtained  here  the  properties  of  the  metal  were  de- 
termined. 

The  main  work  upon  aluminum  was  left  to  H.  St.  Claire  Deville, 
who  devoted  his  life  to  the  study  of  Aluminum.  In  1845  Deville, 
although  ignorant  of  Wohler's  work,  passed  aluminum  cloride  over 
potassium  and  instead  of  getting  the  aluminum  proto-clori de  he 
obtained  the  pure  metal.  Recognizing  the  importance  of  his  work 
the  Acd.  of  Sciences  donated  two  thousand  francs  for  the  contin- 
uance of  his  work.  His  first  attempts  were  the  decomposition  by 
the  use  of  a battery,  but  this  method  was  not  successful  so  he 
turned  to  the  use  of  sodium  as  a reducing  agent.  By  this  means 


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5. 


a quanity  of  the  metal  was  prepared,  after  which  Napoleon  III.  gave 
him  permission  to  continue  his  work  at  the  Emperor's  expence.  By 
thiB  method  Deville  was  given  ample  funds  to  pursue  his  research 
and  he  was  aided  at  this  time  by  two  young  chemists,  Chas.  and  Alex 
Tissier.  These  two  afterwards  left  Deville  and  ipened  up  plants 
of  their  own.  Deville  operated  plants  by  which  aluminum  was  re- 
duced by  sodium  and  these  plants  started  in  France  ran  for  a num- 
ber of  years  and  turned  out  a quanity  of  the  pure  metal. 

From  this  time  on  the  principle  endeavors  were  chiefly 
toward  perfecting  the  process  and  reducing  the  price  of  the  metal. 
In  1832  a Company  was  started  in  England  for  the  preparation  by 
the  usual  method  and  a product  of  reasonable  purity  was  obtained. 

At  this  time  came  the  wonderful  invention  of  H.  Y.  Castner  of  New 
York  on  tne  production  of  sodium.  This  invention  reduced  the  price 
of  sodium  by  seventy  five  per  cent.  Mr.  Webster  of  the  plant  in 
England  induced  Mr.  Castner  to  open  up  a plant  in  England  in  which 
both  processes  were  imployed.  This  plant  was  built  in  1883  and 
turned  out  100,000  pounds  of  aluminum  annually.  The  following 
table  gives  an  indication  of  the  price  tend  of  aluminum. 

Table  II2 

Price  of  Aluminum 

1854  1855  1856  1857  1853  1859  1878  1890  1891  1895 

^/lb. 

on  cont.  259.2  103.50  32.9  25.92  17.33  11.34  2.98  1.30  0.32 

The  first  commercial  attempts  were  about  1885  toward  elec- 
trical decomposition.  Of  these  processes  which  were  patented  at 
that  time,  those  of  Cowles,  Herault,  and  Hall  stand  forth.  Chas. 
k.  Hall  of  Oberlin  Ohio  prepared  a bath  of  fused  cryolite  with  the 
alumina  dissolved  in  it.  An  electric  current  was  used  to  precipi- 


, 


' 9 ’ c 

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6. 

tate  the  pure  aluminum.  This  process  was  the  wonder  of  the  times 
as  it  reduced  aluminum  to  a commercial  price  with  maximum  of  purity. 
This  process  has  been  the  outstanding  one  wvery  since  that  time 
and  it  seems  to  be  the  main  one  for  many  years  to  come. 

The  difficult  thing  now  is  the  preparation  of  the  pure  alum- 
ina. In  the  early  days  of  aluminum  production  the  preparation  of 
the  alumina  was  tather  simple.  In  a large  number  of  cases  the 
mineral  cryolite  (AlgS’gSUaF  ) was  used.  Alumina  was  also  prepared 
by  the  ignition  of  ammonium  alum  or  an  alum  free  from  iron.  Bauxite 
was  also  used  and  alumina  prepared  by  the  fusion  with  sodium  car- 
bonate and  formation  of  sodium  alurainate.  This  alurainate  was  then 
extracted  with  water  and  filtered.  Carbon  dioxide  was  then  passed 
through  the  clear  solution  and  aluminum  hydrate  formed.  This  hyd- 
rate was  then  filtered,  sodium  carbonate  regenerated,  and  the 
hydrate  calcined  to  alumina.  But  at  the  present  time  alumina  is 
prepared  exclusively  by  the  MBAeyer  pro  cess M.  In  this  process  the 
ore  is  ground  fairly  fine,  kilned  to  destroy  the  organic  matter, 
and  mixed  with  a solution  of  caustic  soda  to  a sp.gr.  of  1.45  at 
a pressure  of  seventy  pounds  per  sq.  inch  for  eight  hours.  The 
mass  is  then  blown  into  a tank  by  its  own  pressure  and  water  added 
to  a spec.  grav.  of  1.25  so  as  not  to  ruin  the  asbestos  filter  which 
removes  the  hydrates  of  iron  and  silica.  The  sodium  hydrate  is 
agitated  with  alumina  for  thirty  six  hours  when  approximatly  seven- 
ty per  cent  of  the  alumina  in  the  solution  will  be  precipitated. 

The  Alumina  is  then  filtered,  washed,  and  partially  dried.  The 
filtarte  is  then  concentrated  to  1.45  and  used  for  another  batch  of 
solution.  The  precipitate  is  finally  calcined  at  1000  degrees  to 
insure  proper  crystalline  form. 


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7 


The  mystery,  romance  and  financial  promise  of  aluminum  have 
attrached  chemists  and  technical  men  from  all  the  world.  Enorm- 
ous amounts  of  work  have  been  done  upon  the  manufacture  of  the 
metal.  But  it  is  readily  seen  that  the  amount  of  work  yet  to  be 
done  is  stupendous.  The  results  of  these  men  are  shown  in  the 
numerous  patents  in  the  Capitals  of  the  various  nations.  But 
these  processes  have  not  brought  forth  any  startling  advances.  The 
various  methods  for  the  purification  of  the  alumina  all  follow  the 
same  principles;  a reduction  with  an  alkali  or  an  alkali  earth;  a 
replacement  by  an  active  gas  as  a halogen  or  carbon  dioxide;  or  a 
pure  solution  with  a strong  solvent. 


* 


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> 


3. 

Ill  THEORETICAL 

The  preparation  of  alumina  for  the  manufacture  of  aluminum 
must  be  a true  commercial  and  economic  process.  The  old  time 
processes  of  fusion  with  sodium  carbonate  or  ignition  of  an  alum 
can  not  be  considered  for  several  reasons.  Pirst  is  the  limited 
supply  of  the  mineral  with  which  they  are  concerned;  second  the 
obious  cost  of  materials  and  the  waste  which  they  produce.  At 
the  present  time  we  are  preparing  alumina  by  the  Baeyer  process 
which  I have  previously  describe  in  the  Historical  section.  This 
is  a good  method  an  economical  one  if  we  have  a large  supply  of 
the  proper  mineral  to  work  with.  In  order  for  this  process  to  be 
commercial  the  alumina  content  must  be  above  fifty  per  cent,  the 
Siog  content  below  15  percent,  and  the  Fe£03  and  Sio2  con‘t®n't 
correspondingly  low.  How  this  imposes  narrow  specifications 
upon  the  use  of  this  process  as  today  only  certain  bauxites  are 
used.  It  is  necessary  that  this  process  be  improved,  a larger 
supply  of  the  mineral  opened  up,  or  a new  process  developed. 

In  looking  up  the  literature  upon  this  subject  we  are 
surprised  with  the  scores  of  patents  issued  for  the  manufacture 
and  purification  of  alumina.  But  when  we  study  these  we  find 
that  they  all  simmer  down  to  really  a few  which  hold  the  gen- 
eral principles  for  them  all.  So  we  will  here  mention  a few 
showing  what  is  being  done  in  the  line  of  new  processes. 

We  find  a number  of  the  new  processes  depending  upon  the 
solvent  action  of  some  acid  or  alkali.  United  States  Patent  I, 
301,394  was  issued  for  the  decomposition  of  aluminous  ores  with 
sulphuric  acid.  The  aluminum  dissolved  was  converted  into  the 
alum  by  the  addition  of  potassium  sulphate.  Then  the  alumina  was 


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' ; * 


prepared  by  ignition  and  the  K2SO4  was  regenerated.  How  this  pro- 
cess makes  it  necessary  that  the  aluminum  material  present  be  sol- f 
uble  in  sulphuric  acid.  And  it  is  a fact  that  only  a small  por- 
tion of  our  aluminous  ores  have  the  aluminum  held  in  a sulphuric 
acid  soluble  condition. 

Reduction  processes  have  been  rather  popular  since  the 
discovery  of  aluminum.  Mr.  H.  A.  Richmond  has  developed  a process 
along  these  lines.  This  process  consisted  in  mixing  kaolin, 
pyrites,  and  carbon  in  the  proportions  of  132,120,21.  This  mixture 
was  heated  in  an  electric  furnace  to  a high  temperature  where  the 
alumina  formed  as  a molten  layer  on  top  of  the  molten  iron. 

Carbon  monoxide  and  SiS2  are  given  off  as  a gas.  Where  sulphur 
is  used  instead  of  the  pyrites  the  alumina  was  practically  pure. 

The  process  is  valuable  as  it  takes  care  of  the  iron  present  in 
the  ore  which  is  always  a very  troublesome  element.  This  process 
seems  to  be  of  considerable  value  especially  when  the  time  comes 
for  the  removal  of  aluminum  from  blast  furnace  slags. 

A process  very  similar  to  the  "Baeyer  Process"  was  developed 
by  B.  J.  Halvorsen  and  issued  in  U.  S.  patent  I, 333, 020. ® This 
consisted  in  treating  labradorite  with  ammonia  in  an  auto  clave 
at  a pressure  of  from  ten  to  fifteen  atmospheres,  for  eight  hours. 
This  is  then  removed  by  decatation  and  filtration  and  heated  to 
150  degress.  Thus  the  alumina  is  formed, the  ammonia  is  regenerated 

Louis-Gabriel  Patrouilleau  worked  upon  a silica  aluminous  ore 
which  was  very  nearly  free  from  iron.  He  heated  the  ore  to  a 
dark  residue  and  then  passed  clorine  gas  thru  it.  This  gave  the 

j 

clo rides  of  silica  and  aluminum.  The  Si  cl  4 was  decomposed  with 
water  and  the  H2Si04  was  separated.  The  hydro  clo  ric  acid  was 


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' 1 


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10. 

expelled  upon  evaporation.  Thio  process  has  the  obvious  diffi- 
culty that  it  must  be  free  from  iron  when  in  reality  it  is  very 
hard  to  obtain  an  aluminous  ore  which  does  not  contain  more  or 
less  iron. 

An  unusual  process  is  that  of  E.  E.  Dutt  in  which  ASgOg  is 
used  instead  of  the  So2«  Olay  is  acted  upon  at  a red  heat  by  the 
oxide  in  the  presence  of  calcium  cloride.  The  calcium  aluminate 
formed  is  treated  with  aluminum  cloride  and  water  and  the  result 
ing  product  is  the  aluminum  hydroxide.  This  aluminum  hydroxide 
is  then  calcined  to  alumina.  This  process  seems  to  have  some 
promise  to  it  but  for  economical  reasons  it  would  probably  run 
into  difficulties. 

So  that  in  examining  a clay  or  a mineral  as  to  its  poss- 
ibilities in  the  aluminum  industry  there  are  no  precedents  to 
follow.  Each  investigar  has  a problem  of  his  own  depending  upon 
the  ore  used. 


> : '■  . K y ■ 

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11. 

IV  EXPERIMENTAL 

The  samples  of  the  material  used  in  this  work  were  obtained 
from  Dr.  Parmelee8  of  the  Dept,  of  Ceramics  of  the  University  of 
Illinois.  The  samples  were  obtained  by  that  department  from  de- 
posits in  the  state  of  Missouri  which  are  situated  along  the  C.  R. 
I.  & P.  railroad  in  the  counties  of  Pranklin,  Gasconade,  and 
Maries.  These  deposits  have  been  worked  fro  some  time  and.  the 
product  used  for  the  manufacture  of  abrasives  and  of  refractories. 
There  were  no  figures  available  as  to  the  possible  extent  of  the 
deposits  but  they  have  long  been  looked  upon  as  a possibility  in 
the  manufacture  of  aluminum.  The  clay  is  a rough,  sandy  looking 
material  with  a yellowish  or  somewhat  reddy  appearance.  The  clay 
is  of  a diaspore  composition. 

The  analysis  of  this  material  was  made  by  a sodium  carbonate 
fusion  in  a platinum  crucible.  By  this  means  everything  went  into 
solution.  The  fusion  was  carried  out  in  the  ordinary  way  and  re- 
sulting material  was  dissolved  in  HLC  and  evaporated  to  dryness. 

It  was  then  taken  up  with  water  and  again  evaporated  to  dryness. 
The  residue  was  taken  up  with  water  and  the  J^SiC^  had  impurities 
of  aluminum  hydroxide  so  the  silica  was  dissolved  in  HP  and  the 
residue  ignited  and  weighed.  This  loss  in  weight  gave  the  correct 
amount  of  silica  in  the  sample.  The  aluminum  present  in  the  sam- 
ple was  precipitated  with  NH^OH  and  NH^Cl,  filtered,  ignited  and 
weighed.  The  Pe  present  in  the  aluminum  was  dissolved  out  with 
HCh  and  Lc  titrated  with  standard  Kuno^.  The  loss  in  weight  of  the 
aluminum  gave  the  correct  amount  of  aluminum  present.  The  calcium 

and  barium  were  precipitated  from  the  aluminum  hydroxude  filtrate 
by  (NH4)2c2°4  and  filtered  ignited  and  weighed.  The  following 
table  _gj.v_eB  t h e,.„analyji.^-. 


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Table  III 


12 


Analysis  of  Missouri  Olay 

Moisture  — 0.33$ 

Si02  — — 11.70 $ 


Alumina 
Calcium  (CaO) 

Fe2°3 


80  • 80$ 

5.2 

I . 35$ 


total  99.98 

This  analysis  was  also  made  by  Dr.  W.  S.  Cox9  in  which  he  found 
the  analysis  to  bei- 

Table  IV 

Analysis  of  Missouri  Clay  (By  Dr.  W.  S.  Cox) 


Moisture 

0.60$ 

Wat  er 

14.00$ 

Si02 

9.30  $ 

a12°2 

-73.73$ 

Fe2°S 

0.57$ 

Nago 

2.00$ 

k2o 

— — 0.52$ 

The  clay  was  then  attacked  as  to  its  stability  to  acids  and 
alkalis.  A sample  was  treated  in  a casserole  with  the  solvent  for 
two  days.  This  was  taken  to  dryness  if  possible  but  in  the  case 
of  sulphuric  acid  the  final  step  was  then  heating  to  dryness  with 
a flame.  The  residue  was  taken  up  in  water  and  filtered  and  ignited 
to  dryness  and  weighed.  This  gave  the  amount  of  material  which  had 
been  decomposed  by  the  solvent.  The  water  soluble  portion  was  then 
neutralized  and  made  slightly  acidic.  MH  oh  and  1TH  OH  were  added  to 


. 

. 


13. 

excess  and  the  aluminum  hudroxide  was  filtered  off,  ignited  and 
weighed.  This  gave  the  amount  of  aluminum  which  the  solvent  had 
dissolved  from  the  sample.  This  proceedure  was  followed  out  with 
the  solvents  H2S04  (cone.),  H2SQ4  (dil.),  Aqua  Regia,  NaOh  (10  N. ) 
and  KOH  (10). 

Table  V 

Decomposition  of  clay  by  acids  and  alkali 


20 . 4 c/o 

13.5  # 

16.5  # 
22.7  # 

20.90  # 


With  HoS0/  (cone.) 

" K2S04  (dil.  ) 

M Aqua  Regia 
M NAOH  (10  N.) 

" KOH  (ION.) 

The  amount  of  alumina  which  was  dissolved  from  the  sample  was 
calculated  on  the  assumption  that  there  was  no  Iron  present. 

Table  VI 

Per  Cent  of  Alumina  Dissolved  from  Sample 

With  H2S04  (cone.)  20.4# 

" H2S04  ( dil.)  13.5# 

H Aqua  Regia  4.54# 

NaOH  (10  N.) 

KOH  ( 10  N.) 

Alumina  per  cent  of  total  Alumina  Content 
With  H2S04(conc.)  — 25.2# 

" H2S04(dil.)  — -16.7  # 

'•  Aqua  Regia  — ~ 5.12# 

" NaOh  (10  N.)  —28.1  # 

KOH  (ION.))  —.25.$# 


——22.7  # 
20.90# 


ii 


V.  DISCUSSION  OF  RESULTS 


14 


The  aluminous  material  which  is  obtained  from  the  counties  of 
Franklinn,  Gasconade,  and  Maries  in  the  State  of  Missouri  has  no 
commercial  value  for  the  manufacture  of  alumina  by  chemical  solvent ;i 
without  the  aid  of  high  pressure  and  high  temperature.  In  order 
for  a mineral  to  be  such  it  should  give  up  at  least  fifty  per  cent 

i 

of  its  alumina  to  a fairly  cheap  solvent  which  might  be  regenerated, 
and  used  continously.  In  the  examination  of  this  material  I have 
used  the  beet  and  strongest  solvents  which  we  have  knowledge  of, 
and  in  no  case  have  satisfactory  results  been  obtained.  I find 
that  it  was  impossible  to  dissolve  more  than  twenty  two  per  cent 
of  the  mineral  or  was  it  possible  to  change  more  than  twenty  five 
per  cent  of  the  alumina  present  into  a soluble  form.  This  was 
sufficient  evidence  to  show  that  the  aluminum  was  present  in  the 
mineral  as  a silicate  or  other  insoluble  form.  And  this  would 
render  that  mineral  unsuitable  for  working  with  chemicals. 

But  the  value  of  this  ore  as  an  aluminous  material  does  not 
necessarily  lie  in  its  susceptability  to  solvents.  At  the  pre- 
sent time  the  aluminum  industry  has  in  use  processes  which  are 
truly  economic  ones.  They  make  several  requirements  which  the 
mineral  must  fulfill  before  it  can  be  of  use.  That  is  they  re- 
quire that  the  alumina  content  must  be  high,  the  silica  content 
must  be  low,  the  iron  and  titanium  contents  must  also  be  low. 

These  requirements  have  so  far  been  fulfilled  only  by  bauxite. 

But  here  we  have  an  ore  which  is  rich  in  alumina,  which  is  low  in 
silica,  and  which  has  practically  no  iron  and  no  titanium.  This 
mineral  meets  the  requirements  in  all  respects  and  should  be  of 
value  in  respect  to  the  "Baeyer  Process”.  This  process  uses  a 


. 


. 

. 


. 


. 

* 


* 


15. 

a high  pressure  and  heat  to  break  down  those  bonds  which  hold  the 
aluminum  in  the  mineral.  And  that  is  obviously  the  only  method  of 
attack  sonce  is  so  inert  to  the  action  of  our  common  solvents. 


. 


16. 


VI.  SUMMARY  OF  RESULTS 


I.  The  analysis  of  the  clay  given. 

II.  The  Analysis  agrees  with  that  of  other  investigators. 

5.  The  alumina  content  was  shown  to  be  higher  than  was  supposed. 

4.  The  stability  of  the  mineral  to  acids  and  alkalis  was  shown. 

5.  The  amount  of  the  alumina  present  which  w as  susceptible  to 
common  solvents  was  shown. 

6.  The  aluminum  was  shown  to  be  present  as  the  silicate  rather 
than  the  aluminate. 

7.  The  clay  was  shown  to  be  undesirable  for  easy  chemical 
decomposition. 

8.  It  was  shown  that  the  clay  was  in  all  probability  desirable 
when  applied  to  such  a process  as  the  "Baeyer  Process." 


. 

. 


. 


. 


17 


VII  BIBLIOGRAPHY 


1.  G.  A.  Roush,  Mineral  Industry,  29*  7 (1920) 

2.  Minet  The  Production  of  Aluminum  (1905) 

3.  Oliver,  R.  S, 

U.  S.  Patent  1,301,  394 

Laist,  P. 

Chern.  Abstr.  13  1907  (1919) 

Freiche,  F.  F. 

4.  Richmond,  H.  A.  U.  S.  Patent  1,245,383 

Chem.  Abstr.  12  253  (1918) 


5.  Halvorsen,  B.  F.  U.  S.  Patent  1,333,  020 

Chem.  Abstr.  4__  1416  (1920) 


6.  Patrouilleau, 

L.  G.  Fr.  Patent 

481, 

106 

Chem.  Abstr.  12  1337 

(1918) 

7.  Dutt,  E.E. . 

U.  S.  Patent  1,332, 

115 

Chem.  Abstr.  14  1194 

(1920) 

8.  Parmelee, 

Cer tidies  Department, 

Univ 

. Illinois 

9.  Cox,  ¥.  S. 

Am.  Mineralogist  2 

144 

(1917) 

3 

154 

(1918) 

